Extendible wing flap



y 2, 1944- E. o. RICHTER EXTENDABLE WING FLAP 2 Sheets-Sheet 1 Filed June 2, I941 nll w l I Nvflvrok flab", 40 f y 2, 1944- E, o. RlCHTER' EXTENDABLE WING FLAP Filed June 2, 1941 2 Sheets-Sheet 2 I NVENTOR 1 Patented May 2, 1944 UNITED I nx'rnnnmm wmo lvin o. Richter, Burbank, CaliL, assignor to Lockheed Aircraft Corporation,

Burbank,

Application June 2, 1941, Serial No. 396,347

Claims. (01. 244-42) i This invention relates to improvements in fiap extending mechanisms for controlling the exten sion and angle of attack of fiaps used to increase wing area/for take-oi! and landing and to serve as landing brakes.

Extensible trailing and nose fiaps of the general type under consideration have been proposed and used heretofore as they are necessary to improve the take-offcharacteristics and reduce the landing speed of modern high performance airplanes,

since without such flaps thespread between landing speed and top speed is a limiting factor in flap and the main airfoil throughout the move ment of the flap.

It is a further object of this invention to provide means for adjusting the leading and trailing fiapedge positions to fair the flap into the surface of the main wing when nested, therein,

. whereby the flap will present the minimum drag. when nested into the wing, without exposed or design, some high speed craft having dangerously high landing speeds, which limit their use to well developed landing fields having long and smooth runways. tended from their nested position in a pocket within the wing profile by means either of arcuate or straight tracks, levers or linkage, the problem being to obtain the most desirable flap position and angle not only at the extreme extension but at intermediate points. For take-oil? purposes a trailing edge flap should desirably form a continuation of the upper surface of the wing when partially extended, except for an offset position thereof to form an air gap; while for landing the fiap should be capable of both full extension and considerable downward Pivotal movement, both to increase the lift and to act as a brake. It will therefore be evident that uniform arcuate or straight line movement of the flap projecting mechanism can not fulfill both requirements. It has heretofore been proposed that a straight line projection of the flap be used, followed byipivotal movement thereof after it reaches its extreme Heretofore such fiaps hav been exguiding mechanism wherein separate, guiding position; but such an arrangement does not permit fairing .in thefiap as an extension of the upper surface of the main'wing at intermediatepositions of the flap, such as would desirably be used for take-off. It is accordingly an object of this invention to provide an improved fi'ap extending mechanism that is adapted to give maximum eiilciency in fiappositiomangle and gap between the main airfoil and the flap throughout the range of movement of the flap.

- It is another object of this invention to provide an improved -fiap projecting and guiding mechanism that can be designedfor maximum emciency in flap positioning at intermediate positions as well as extreme positions, and also wherein the angle of attack of the flap can be varied as desired throughout its range of movement. With the arrangement of this invention either or both uiding tracks can be variously curved to control both flap position angle and gap between V the the trailing edge of a wing, showing the arrangeprojecting parts or breaks in the main wing profile.

It is also an object of this invention to provide an improved flap. guiding mechanism entirely housed within the wing profile, while capable of projecting the flap beyond the trailing edge thereof to provide a slot effect for preventing or delaying the stall or burble of the air flow over the upper surface of the flap when the latter is tilted beyond its normal stalling angle for use as a landing brake. t It is still, another object of this invention to provide an improved flap or auxiliary airfoil tracks or channels control the movement of spaced levers in such a way as to approximate a quadrilateral figure having one side controlled by the tracks to vary the tilt of a fiap carried by the opposite side thereof.

It is also an object of this invention to provide the proper gap between the main airfoil and the flap-at all points in the range of the fiap motion thus insuring the proper aerodynamic conditions for satisfactory operation.

. Other and'further important objects of this invention will be apparent from the disclosures in the specification and the'accompanying drawings.

This invention in its preferred form is illustrated in the drawings and hereinafter more fully described. v g

In the drawings:

Figure I is a fragmentary cross-section through v ment of'the trailing airfoil or flap and its guiding and extending medianism, the flap being show in its retracted or nested position.

Figure II is an enlarged fragmentary showing 7 similar to Figure I wherein the flap is shown in its fully. projected and deflectedposition,

Figure III is a diagrammatic showing,xto a re duced scale, of the flap at an intermediate extension to illustratehow it fairs with the upper wing surface, while providing a-gap for the flow of air v therebetween.

Figure IV is an enlarged section on the line IV-IV of Figure I showing roller mounting.

the track and g ide 2| opposite the trolley22 second cable end 32 ing an upper skin I l and lower skin l2, the latter being cut away to form a pocket or opening for a flap or auxiliary airfoil l3 which is adapted to nest inside the wing profile with its lower surface of the link pivots 35 and 31 will result in pivotal l4 forming an aligned continuation of the lower skin I2 of the wing. Preferably, the flap is of a size that can be adequately handled by supporting and guiding mechanism at each end thereof, so that in a large airplane it would be desirable to use a plurality of flaps for each wing, a corresponding number of main wing ribs or bulkheads i0 eachserving to support theedges of adjacent flaps. With this arrangement Figure IV would have the tracks and structure symmetrically duplicated on either side in the case of the inter- 25 I6, and the angle of the flap is controlled by a 30 second lever l'l guided by a second track H3. The flap ends of the two levers on each end of the flap are pivoted at l9 and to brackets 2| thereon; for convenience Figures I and H Show one bracket in full lines with the near side levers broken away adjacent thereto to show the far side levers and tracks against the background of a rib l0. As shown and described herein, the lever I5 is intended to carry the major load on the flap, and to project and retract the same, while the second lever I8 is used to control the angle of the flap. Since the first lever l5 controls the projection of the flap, it is guided on it track I G by a trolley 22 near the mid-point thereof, with a second guide roller 23 at the forward end of the lever. While both or either of the tracks l6 and 18 could be of channel or beam -form, and either lever and track could be used as the projecting control, I have chosento show a T type-track for the upper lever, which requires rollers on both sides of the leg of the T, to stabilize the lever. Accordingly, I provide idler rollers and 25 opposite theroller .23. Also, rollers 26 bear against the edge of the leg of the T to prevent cocking of the lever. It will be noted that the trolley 22 comprises two rollers 21 having a common pivot 28 to' permit alignment thereof. With this arrangement the T-track It can be straight or curved as desired,

I to project the flap in controlled relationship with the trailing edge of the .upper skin, to provide a slot in connection therewith, the arrangement being indicated in the diagrammatic showing 'of Figure 111 wherein the flap is shown as partially extended. a Control of the outward (or rearward) and return movements of the flap may conveniently be arranged as aremotely controlled cablesystern wherein one end of a cable 29 is led over a pulley 30 above and near the outer end of the track Ii, andis attached to the lever l5 at its inboard (or forward) end, to draw the same outwardly; a

below, and attached to the lever is to retract the mediate ribs, but it is considered unnecessary to complicate the drawings by such a showing.

The flap or airfoil i3 is suspended or supported from the ribs N by a lever l5 guided by a track being led over .a' pulley H 33 ating these cables, at the will of the pilot, may be incorporated in the general design, manual and hydraulic systems having been heretofore used for such purposes.

5 The angle of the flap relative to the mean chord of the wing is controlledby the second lever l1 and its track I8 in connection with a short link 34, pivoted at one end 35 to the end of the lever H which carries a roller 36 engaging in the chan- 10 nel of the trackv l8, and pivoted at its other end 31 to the first lever l5. This arrangement forms a quadrilateral figure comprising the levers l5 and II, their mounting bracket 2| on the flap l3, and the link 34, so that variation of the spacing movement of the link 34 with a distortion of the quadrilateral figure that results in a proportionate pivotal movement of the flap l3, thus controlling its angle. This result can be accomplished 2 to any desired extent at any point in the flap travel by variation in either or both of the tracks 16 and I8. I have chosen to show the track It as arranged to begin to tilt the flap to an increasedangle of attack as it is projected beyond of the flap to a maximum at its extreme extension, but obviously the angular motion of the flap can be predetermined as desired by proper shaping of either track.

With this arrangement the movement of the flap relative to the upper surface of the wing can be closely controlled as desired, so that the flap can function as a smooth continuation thereof at partial promotions, to provide the most efficient 3,; lift increasing effect as for take-oil, while at further projections the flap can be increasingly its mid-point and to increase the angle of attack tilted downwardly to increasethe drag' effect and I thus serve more efliciently as a landing brake, while also reducing the wing loading.

40 In order to fair the retracted flap into the wing profile, 'I have provided eccentric adjustments for two of the pivots in the quadrilateral figure, as shown in Figure V. By mounting the end 31 of the link 34 on an eccentric pin 38, ad-

justment of the eccentric pin distorts the quadrilateral flgure to raise or lower the trailing edge of the flap to fair the same into the wing profile. A similar eccentric pin at l 9 in the bracket 2| will fair in the leading edge of the flap. In practice it is preferable to adjust the leading ed e before the trailing edge. After the adjustment has been made a lock plate 39 is applied over the head of the pin 38 to retain the adjustment.

, The lower lever 11, in its partially extended 5 position, requires a notch (not shown) in the lowerskin I2 ofthe wing,ahead oftheflappocket. this notch being conveniently closed when the flap is retracted by a piece of material lll attached to the lever ll adjacent its pivot 20 on the bracket 2|.

improved and simplified flap controlling and guiding mechanism that provides a predetermined control of the flap angle and position at all points of the travel thereof.-

. Having thus described m invention and the present preferred embodiment thereof, I desire to cm the fact that many modifications may beresortedtoinamannerlimitedonlybyajust 7c interpretation of the followins claims. a

same. guy convenient method or remotely oper- 1 tracks mounted in'said airfo l adjacent each side It wfll thus be seen that I have provided an 2,848,150 g H shift one end of the pivoted link relative tattle or said flap, a pair of levers each supp rted by one of said guide tracks and movable thereon, said lever each having one end thereof pivotally attached to said flap in spaced relationship to each other, one of said levers having a two point support on its track whereby its angular position relative to said airfoil is-determined by the angle or curvature of its track, the other of said levers being iournaled at its other end in the other of said tracks whereby the relative angles and curvatures of said tracks varies the position of the free end of said second lever relative to the first lever, and

a link pivotally connecting the free end of thesecond lever to said first lever whereby the'link,

the pair of levers and the spaced pivotal mounting thereof on the flap forms a deformable quadrilateral wherein movement of the free end of the second lever as restrained by the link is adapted to pivot said flap relative to the airfoil.

2. In the combination of claim l,- means for adjusting the position of the -fiap when nested in the airfoil, comprising eccentrically adjustable pivotal connections between oppositely disposed pivots or said levers, link and flap, one adjustable connection being adapted to align the leading edge of the flap into the airfoil profile and the other connection being adapted to align the trailing edge of the flap.

3. In combination with an airplane wing and an extensible trailing edge flap normally nested in a other lever whereby to distort said quadrilateral and thereby produce pivotal movement of the flap due to relative movements between the spaced pivotal connections of the levers engaging the flap.

4. In combination with an airplane wing and an extensible trailing edge flap normally nested in a pocket beneath said wing, a mounting ifor controlling said flap including a pair or levers having spaced pivotal connections at one end to said flap, a pivoted link extending from the other end of one lever to an intermediate point on the other lever,

' the pivotal points defining a quadrilateral, and

guide means for one of said levers for projecting said flap in a predetermined path, and guide means for the other lever adapted to vary theangular position or the pivoted link connecting said levers whereby to distort such quadrilateral with a corresponding angular change inthe position of the flap forming a part thereof.

- 5. In combination with an airplane wing and an extensible edge flap normally housed therein in its retracted position, a mounting for guiding and controlling the extension'oi' said flap, comprising a quadrilateral linkage having pivoted connections, the flap being adapted to form one side of aid linkage, separate guiding means for the members of said linkage engaging said flap, said guiding means being adapted to variably shift the pocket beneath said wing. a mounting for controlling said flap including a pair of levers having spaced pivotal connections at one end Ito said flap, a pivoted link extending from the other end of one lever to an intermediate point on the other lever,- the pivotal points defining a quadrilateral. and guiding means cooperating with said levers to remaining side of said quadrilateral linkage whereby to alter the angle of said flap, and means for adjusting the initial arrangement of said quadrilateral linkage,lcomprising eccentric pivots in at least one of the comers thereof adapted to adiust the initial or nested position of said flap in saidwing. a

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